.. Anyway, you can ask topic starter why he need split, while he just needs to

I'm sorry, but you've missed my point :) I am questioning the wisdom of your suggestion for an alternative approach.

Since OP already decided on a hash-of-hashes, why switch back to a simple hash? Or hash-of-array-?emulation?

Why throw away the benefits of easy lookup?

There has to be some benefit to doing it differently; and few drawbacks